WO1986002507A1 - Satellite telecommunications system - Google Patents

Satellite telecommunications system Download PDF

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Publication number
WO1986002507A1
WO1986002507A1 PCT/DE1985/000374 DE8500374W WO8602507A1 WO 1986002507 A1 WO1986002507 A1 WO 1986002507A1 DE 8500374 W DE8500374 W DE 8500374W WO 8602507 A1 WO8602507 A1 WO 8602507A1
Authority
WO
WIPO (PCT)
Prior art keywords
transmission
satellite
characterized
switching
system according
Prior art date
Application number
PCT/DE1985/000374
Other languages
German (de)
French (fr)
Inventor
Peter Dondl
Original Assignee
Siemens Aktiengesellschaft
Ant Nachrichtentechnik Gmbh
Messerschmitt-Bölkow-Blohm Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DE3437317A priority Critical patent/DE3437317C2/de
Priority to DEP3437317.9 priority
Application filed by Siemens Aktiengesellschaft, Ant Nachrichtentechnik Gmbh, Messerschmitt-Bölkow-Blohm Gmbh filed Critical Siemens Aktiengesellschaft
Publication of WO1986002507A1 publication Critical patent/WO1986002507A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18539Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
    • H04B7/18541Arrangements for managing radio, resources, i.e. for establishing or releasing a connection for handover of resources
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851Systems using a satellite or space-based relay
    • H04B7/18517Transmission equipment in earth stations
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/05Electric or magnetic storage of signals before transmitting or retransmitting for changing the transmission rate

Abstract

In a radiotransmission system via earth satellites (2, 4) which are active from the radiocommunications aspect only during a part of their revolution time and are separated in cycle succession from similar satellites at approximately the same celestial point, interruption-free telecommunications must be ensured between two earth broadcasting stations, despite switching from one satellite to another. This is achieved by interrupting the transmission of the desired signal on the transmission paths (13, 23) in one of the small time-windows reserved for satellite switching from the emitting earth communications station (13). The incoming or outgoing terrestrial signal flow across the land sections (10, 20) is, however, maintained without interruption by charging an emission buffer memory (11) or by discharging a reception buffer memory (21).

Description

Telecommunications Satellite system

The invention relates to a communications satellite system having a plurality of earth satellites, which appear in cyclic sequence at virtually the same point in the sky and alternate in the radio operation with at least one transmitting and at least one receiving earth station today.

In radio transmission method via satellite, it is important that the telecommunications transmission of useful signals continuously and without interruption of going equipped. Especially in the transmission of digital signals, the constant velocity transmission to the ends of the terrestrial satellite link because of the accurate time clock is also important.

In geostationary satellite systems hardly anything will change in the geometry of the spark gaps, and therefore such a system can be operated radio and transmission technology in a conventional manner. In satellite communications systems in which the satellites are only a part of their circulation time staying in the viewing area of ​​their earth stations and replaced in a given time and point in the sky from other satellites of the same telecommunications function (Wadsworth, D. v. Z .: Longitude reuse plan doubles communication satellite capacity of geostationary are; 8. IAJAA Conference, Orlando Florida in 1980, Dondl, P .: Loopus opens up the satellite radio a new dimension, NTZ archive 5 (1983), No. 12, pp 327-335), are switching the telecommunications function from one to other satellite problems, such as the risk that occur on the downlink temporal overlap between the transmissions of both outgoing and incoming satellites that should be avoided. These problems are caused by the fact that not both satellites that replace each other may be the same geometric point in precisely and also some rail tolerances and tolerances for the time of switching must be accepted.

The object of the invention is based is to ensure continuous useful signal transmission via satellite becoming detached from the terrestrial interfaces of earth stations.

This object is inventively achieved in that the transmitting earth station includes a switching device by which the transmission of the digital useful signal is interrupted for a relative to the total transmission time comparatively short time that the switching means is activated together with the switching of the transmission from one of the following satellite in that the transmitting earth station little minutely include a reception buffer at least one transmission buffer store and the receiving earth station, that the transmission buffer between the switching device and the source for the digital useful signal and in that the transmission of the digital useful signal via the satellite with respect to the original transmission rate slightly increased speed he follows. Further embodiments of the invention are specified in the subclaims.

An embodiment of the invention is explained with reference to FIG. 1. Shown is the curvature of the earth 1 is provided with a transmitting earth station 12 and 22, a receiving earth station In the relevant part of the satellite trajectory is symbolically sketched with three satellite positions, wherein 2 to the be detached, at 4 to the detaching and at 3 a at the reversal point that arrived satellite is. The arrows symbolize the hops up

13 and 23. Under the downward earth stations, the transmission 11 and reception buffer 21, and the interfaces 10 and 20 are shown for terrestrial telecommunications network. In this case, in the connection between the transmit buffer memory 11 and transmitting earth station 12, a switch 15 is inserted in place of the transmission buffer memory 11 is the output of a pseudo-random generator

14 may be connected to the earth station. The control of the changeover switch 15 is carried out via a control line 16 from the transmitting earth station.

In Fig. 1, the useful signal, in a short time window in which the switching time between the two outgoing and incoming satellite falls interrupted either by the transmitting earth station transmits a filler signal such as a spezifierten bit pattern or inserts a transmission pause. During this interruption of the useful signal in the buffer memory 11 of the transmitting earth station 12 the delivered via the interface 10 information signals are cached. In addition, is switched via the control line 16 from the transmitting earth station 12, the changeover switch 15 selectively either to the no-contact or the contact, to which the output of the pseudo random generator 14 is connected. In the latter case is supplied with a pseudo-random signal during the switching of the transmitting earth station 12 from the satellite 2 to the satellite 4 of the transmitting earth station 12th If the time window in the signal arrives at the receiving earth station 22, the signals that have been transferred over the forward-flying satellite 2 just before the switch over time, popped from the receive buffer memory 21 for interruption to maintain the useful signal via the interface 20th At the end of the time window, the useful signal back up over the detaching satellite 4 is taken. This useful signal will operate continuously or average until next Umschaltezeitfenster slightly faster than slowly discharged via the two terrestrial interfaces 10 and 20. In this process, the transmit buffer 11 and the receive buffer memory 21 loaded in order to be prepared for the next time window for satellite switching ,

This principle can be applied not only in the continuous signal transmission, but also in zeitgestaffeltem multiple access (TDMA Time Division Multiple Access). However, here is another problem koπimt added, namely the position uncertainty of the satellite at the beginning of transmission. Here, it may happen that the transmission bursts overlap (TDMA bursts) of a plurality of transmitting earth stations accessing each other of the small guard time between the transmission bursts of time because of a small track deviation. also to prevent this, the guard times between the transmission bursts are increased. This measure will take at least until each transmitting earth station of the (TDMA) reference station which may be present on board each satellite also about the time difference and the necessary correction of their transmission shock in (TDMA) is informed access time frame. Transmission and receiving buffer memories 11 and 21 also provide the required for bridging the increased guard times additional storage capacity.

The magnification of the guard times between the transmission shock may be accomplished either by extension of the access time frame or by shortening of the transmission bursts. A combination of both methods is also possible.

In order for satellites on orbits whose location is to satellite switching within the active path phase to earth stations involved closest to keep the signal propagation delay as low as possible, the reception-side Nutzsignalspeicherung that compensates for satellite motion, for bridging the Umschaltezeitfensters and the extended guard times between the will send shock used.

This is done in detail in the following stages:

In the first stage, the guard times between the transmission bursts of the various earth stations in accordance with the above-described possibilities to be extended. This allows the transmission buffer memory 11 of the earth stations involved is even more loaded because the useful signals are sold at a lower transmission rate to the satellite by the greater protection times when on the terrestrial interface 10. This process will take at least the term of the reference station and back. The receive buffer is further drained in order to get the Nutzsignalfluß via the terrestrial interface 20 upright.

In the second stage, which lasts until the time at which the respective satellite has reached its farthest point, the Nutzsignalübertragungsgeschwindigkeit is increased over the radio field 13 so that the charged in the transmission buffer memory 11 useful signals plus further supplied via the terrestrial interface 10 payloads are transmitted to the end of this second stage, and at this time the charges according to the invention resulted in the transmission buffer memory 11 be zero.

In the third stage, which lasts until the beginning of Umschaltezeitfensters, the Nutzsignalübertragungsgeschwindigkeiten over the terrestrial interfaces 10 and 20 and in the upward radio field 13 to the satellite equal to or approximately equal to, wherein causing the approach of the satellite in this phase of its flight, that the Nutzsignalübertragungsgeschwindigkeit in downward radio field 23 from the satellite forth is greater than the upward radio field 13 to the satellite, and thereby the receiving buffer 21 loads each earth station involved so far that it is prepared for the bridging of Umschaltezeitfensters and the increased guard times.

In addition to the previously described, the switching time between the satellites can be chosen so that the satellite 4 to be turned on with certainty further than the auszuschaltende satellite 2; then the resulting thereby additional runtime can replace the transmit buffer in whole or in part.

Is the radial distance of the two satellites 2, 4 to shift time large enough and the switching relative time to the incoming to the satellite signal staggered accordingly so occurs a signal repeating a through turned on satellite 4 that may be used for synchronization in the receiving earth station.

The advantage of the invention is that also non-stationary satellite systems, but flying along defined paths, can be integrated in the existing telecommunications network.

Claims

claims
1. communications satellite system with multiple earth satellites, which appear in cyclic sequence at virtually the same point in the sky and alternate in the radio operation with at least one transmitting and at least one receiving earth station by side, characterized in that the transmitting earth station includes a switching device by which the transmission of the digital useful signal for a relative to the total transmission time comparatively short time is interrupted, that said switching means is activated together with the switching of the transmission from one to the next satellite in that the transmitting earth station includes at least at least one transmission buffer store and the receiving earth station a receive buffer memory, that the transmit buffer between the switching means and the source for the digital useful signal and in that the transmission of the digital useful signal via the satellite with respect to the original About transmission speed slightly increased speed.
2. Telecommunications Satellite system according to claim 1, characterized in that both a transmit and a receive buffer memory are each disposed in both earth stations.
3. Telecommunications Satellite system according to claims 1 or 2, characterized in that during the transmit buffer memory, the read clock has a slightly higher relative to the Einschreibetakt clock frequency, while having at the reception buffer of a Einschreibetakt grow slightly higher clock frequency than the read clock.
4. Telecommunications Satellite system according to claim 1, characterized in that the switching device is designed as a changeover switch, which is transparent in normal operation for the digital useful signal and during the changeover from one to the next satellite to a generator for a defined filling signal, in particular a specified bit pattern is turned on.
5. Telecommunications Satellite system according to claim 1 with zeitgestaffeltem multiple access (TDMA), characterized in that enlarged immediately after the switching of the transfer to the following satellite between the individual transmission bursts (bursts) protection times are adhered to, to each participating transmitting earth station of the TDMA reference station the time deviation and the necessary correction 'the timing of the transmission bursts of the respective Sendeerdfunkstelie is informed in the access frame, that transmit and receive buffers have an additional storage capacity during this time due to connection in each case of a further memory to terrestrial the continuous useful signal transmission between the earth stations via the to get upright interfaces to other transmission equipment.
6. Telecommunications Satellite system according to claim 4, characterized in that the increase in the protection times is achieved by extension of the access time frame.
7. Telecommunications Satellite system according to claim 4, characterized in that the increase in the protection times is achieved by shortening of the transmission bursts.
8. Telecommunications Satellite system according to claim 1 or 2, characterized in that the switchover between the satellites is chosen such that the to be turned on satellite (4) with safety further than the auszuschaltende (2) and the additional term resulting therefrom, the transmit buffer memory at least partly replaced.
9. Telecommunications Satellite System according to claim 7, characterized in that the radial distance between the two satellites (2, 4) at the switching time is great, and that the switching is related in time to the incoming at the satellite signal staggered so that a signal repetition by the switched satellite occurs, which is used for synchronization in the receiving earth station (22).
PCT/DE1985/000374 1984-10-11 1985-10-11 Satellite telecommunications system WO1986002507A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE3437317A DE3437317C2 (en) 1984-10-11 1984-10-11
DEP3437317.9 1984-10-11

Publications (1)

Publication Number Publication Date
WO1986002507A1 true WO1986002507A1 (en) 1986-04-24

Family

ID=6247658

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1985/000374 WO1986002507A1 (en) 1984-10-11 1985-10-11 Satellite telecommunications system

Country Status (5)

Country Link
EP (1) EP0177966B1 (en)
JP (1) JPH0556694B2 (en)
AT (1) AT44340T (en)
DE (1) DE3437317C2 (en)
WO (1) WO1986002507A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995025388A1 (en) * 1994-03-17 1995-09-21 Georgy Ivanovich Tuzov Method of multi-station communications for low-orbiting satellite systems and a device for carrying out the said method
WO2000055988A1 (en) * 1997-07-18 2000-09-21 Georgy Ivanovich Tuzov Method and device for high-speed and low-speed communications using low- and medium-orbit satellites

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3607931A1 (en) * 1986-03-11 1987-09-17 Siemens Ag Telecommunications Satellite System to pave quasistationaeren
DE4223995A1 (en) * 1992-07-21 1994-02-03 Kolbe & Co Hans Controlling network for satellite supported signal transmission system - subjecting low bit rate control signal flow, or extra signal of low bit rate, to spectral expansion
FR2735302B1 (en) * 1995-06-12 1997-07-11 Alcatel Espace communication system with geostationary satellites, and terminal station including

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1117011A (en) * 1964-08-27 1968-06-12 Int Standard Electric Corp Satellite communication system
US3940736A (en) * 1973-08-02 1976-02-24 Nippon Telegraph And Telephone Public Corporation Digital code monitor system
US4054949A (en) * 1975-03-13 1977-10-18 Fuji Electric Company Ltd. Stagnation prevention apparatus in an information transmission system
EP0059454A2 (en) * 1981-02-28 1982-09-08 Siemens Aktiengesellschaft Communication satellite system in geostationary loop positions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1117011A (en) * 1964-08-27 1968-06-12 Int Standard Electric Corp Satellite communication system
US3940736A (en) * 1973-08-02 1976-02-24 Nippon Telegraph And Telephone Public Corporation Digital code monitor system
US4054949A (en) * 1975-03-13 1977-10-18 Fuji Electric Company Ltd. Stagnation prevention apparatus in an information transmission system
EP0059454A2 (en) * 1981-02-28 1982-09-08 Siemens Aktiengesellschaft Communication satellite system in geostationary loop positions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995025388A1 (en) * 1994-03-17 1995-09-21 Georgy Ivanovich Tuzov Method of multi-station communications for low-orbiting satellite systems and a device for carrying out the said method
US5898902A (en) * 1994-03-17 1999-04-27 Tuzov; Georgy Ivanovich Method and apparatus for multiple-station communication for low-orbit satelllite systems
WO2000055988A1 (en) * 1997-07-18 2000-09-21 Georgy Ivanovich Tuzov Method and device for high-speed and low-speed communications using low- and medium-orbit satellites

Also Published As

Publication number Publication date
EP0177966A1 (en) 1986-04-16
DE3437317A1 (en) 1986-04-24
EP0177966B1 (en) 1989-06-28
JPS62500765A (en) 1987-03-26
JPH0556694B2 (en) 1993-08-20
DE3437317C2 (en) 1992-05-14
AT44340T (en) 1989-07-15

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